This application claims the benefit of provisional application No. 60/583,260, filed Jun. 26, 2004.
1. Field of the Invention
The present invention relates to roll-back vehicle transport systems and, more particularly, to a system for adjusting the position and alignment of a vehicle being loaded on the platform of a roll-back truck during the loading process.
2. Discussion of the Related Art
The two primary types of service trucks used for transporting vehicles, and particularly disabled vehicles, are tow trucks and carriers. Tow trucks ordinarily lift one end of the automobile so that the wheels are raised above the ground. The automobile is then towed by the tow truck with the wheels on the opposite end of the towed vehicle remaining on the ground. Carriers, on the other hand, are able to support the entire automobile (car, small truck, tractor, golf cart, etc.) above the ground on a flat platform or deck. This allows the vehicle to be transported without relying on the wheels of the towed vehicle to roll along the ground surface throughout the towing process, while also eliminating tire wear and possible damage to the towed vehicle.
The most common type of carrier truck uses a moving platform and is often referred to as a “roll-back” truck. On a roll-back truck, the platform is slidable and pivotable relative to the bed frame between a transport position, at which the platform is parallel and forwardly positioned on the bed frame, and a loading position, at which the platform is moved rearwardly and angled relative to the bed frame so that the rear edge of the platform contacts the ground to define an approach angle. A vehicle to be transported on the roll-back truck is pulled forwardly onto the platform with the use of a cable extending from a winch at the forward end of the platform. Ordinarily, the free end of the cable hooks to the underside of the vehicle frame or chassis, usually at the front end, and the winch is operated to wind the cable and pull the vehicle forward along the upwardly angled platform.
Despite the several advantages of roll-back trucks, as compared to tow trucks, there are several drawbacks associated with roll-back trucks, and particularly the loading process. For instance, it is sometimes difficult to position the rear end of the roll-back truck so that the platform is longitudinally aligned with a disabled vehicle to be loaded on the platform. This problem is often encountered along the side of a highway or road which has an embankment with a steep slope. If the disabled vehicle is off the shoulder of the highway and down the embankment, it may be impossible to safely position the roll-back truck on the embankment so that the disabled vehicle is longitudinally aligned with the centerline of the platform. In this situation, it may be necessary to position the platform at an angle relative to the forward moving position of the disable vehicle. Then, as the disabled vehicle is pulled onto the platform, at an angle, it is necessary to shift the forward end of the disabled vehicle to one side or the other in an attempt to straighten the towed vehicle relative to the centerline of the platform as the towed vehicle is continually pulled forward onto and along the platform. Loading a disabled vehicle (e.g. car, truck, tractor, etc.) onto the platform may also be difficult if the forward or rear wheels of the disabled vehicle are damaged or cannot be steered in a manner which allows the disabled vehicle to roll in the desired path when pulled upwardly along the platform. Presently, shifting the towed vehicle transversely to either side of the centerline of the platform is a laborious and time consuming task which requires attachment and removal of chains to the vehicle in order to pull the vehicle sideways with the use of hand operated jacks. Each time it is necessary to adjust the angle or transverse position of the load, the forward loading operation is interrupted.
Accordingly, there remains a need in the vehicle transport industry for a load leveling system on roll-back trucks. More particularly, there remains a definite need for a system which quickly and efficiently repositions and properly aligns vehicles on the platform of a roll-back truck during the loading process, thereby minimizing the labor and time required to fully load and safely position the vehicle on the platform of the roll-back truck for subsequent transport.